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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Software Development’ Category

Delphi: migrating applications + DLLs that use ShareMem to using FastMM

Posted by jpluimers on 2021/04/22

Notes to myself:

I bumped into some legacy code with a windows process and DLLs both using ShareMem (now System.ShareMem) so that strings could be shared between the instances.

There were lots of memory leaks, so migrating to FastMM was important.

I followed these steps to get rid of ShareMem:

  1. Put FastMM4 at the top of the uses lists for both the application and DLL projects
  2. Remove ShareMem from these uses lists (in fact from any unit used)
  3. Follow the FAQ ensuring these defines are globally in all projects involved: ShareMM;ShareMMIfLibrary;AttemptToUseSharedMM in each project file or the below in a fork of the FastMM4 repository file FastMM4Options.inc
    {$define ShareMM}
    {$define ShareMMIfLibrary}
    {$define AttemptToUseSharedMM}
    
    • Q: How do I get my DLL and main application to share FastMM so I can safely pass long strings and dynamic arrays between them?
    • A: The easiest way is to define ShareMM, ShareMMIfLibrary and AttemptToUseSharedMM in FastMM4.pas and add FastMM4.pas to the top of the uses section of the .dpr for both the main application and the DLL.
  4. Resolve any error like [dcc32 Error] E2201 Need imported data reference ($G) to access 'IsMultiThread' from unit 'FastMM4': in projects that depend on run-time packages. Luckily, how to do that is in the FAQ too:
    • Q: I get the following error when I try to use FastMM with an application compiled to use packages: “[Error] Need imported data reference ($G) to access ‘IsMultiThread‘ from unit ‘FastMM4‘”. How do I get it to work?
    • A: Enable the “UseRuntimePackages” option in FastMM4Options.inc.

Related:

Note:

  • I did not use SimpleShareMem (now System.SimpleShareMem) as the source of it did not tell me anything about FastMM4 compatibility.
  • A long time ago, FastMM changed the EnableBackwardCompatibleMMSharing from the old EnableSharingWithDefaultMM conditional define.

–jeroen

Posted in Delphi, Development, FastMM, Software Development | Leave a Comment »

VMware ESXi 6 and 7: checking and setting/clearing maintenance mode from the console

Posted by jpluimers on 2021/04/21

Every now and then it is useful to be able to do maintenance work from the ESXi console addition to the ESXi web-user interface.

I know there are many sites having this information, but many of them forgot to format the statements with code markup, so parameters with two dashes -- (each a Wayback Unicode Character ‘HYPHEN-MINUS’ (U+002D)) now have become an [Wayback] Unicode Character ‘EN DASH’ (U+2013) which is incompatible with most console programs, especially the ESXi ones (as they are Busybox based to minimise footprint).

Note you can use this small site (which runs in-browser, so does not phone home) to get the unicode code points for any string: [Wayback] What Unicode character is this ?.

Links like below (most on the vmware.com domain) have this EN DASH and make me document things on my blog instead of trying code directly from blogs or forum posts:

So below are three commands I use that have to do with the maintenance mode (the mode that for instance you can use to update an ESXi host to the latest patch level).

    1. Check the maintenance mode (which returns Enabled or Disabled):
      esxcli system maintenanceMode get
    2. Enable maintenance mode (which returns nothing when succeeded, and Maintenance mode is already enabled. when failed):
      esxcli system maintenanceMode set --enable true
    3. Disable maintenance mode (which returns nothing when succeeded, and Maintenance mode is already disabled. when failed):
      esxcli system maintenanceMode get

Some examples, especially an the various output possibilities (commands in bold, output in italic):

# esxcli system maintenanceMode get
Disabled
# esxcli system maintenanceMode set --enable false
Maintenance mode is already disabled.
# esxcli system maintenanceMode set --enable true 
# esxcli system maintenanceMode get
Enabled
# esxcli system maintenanceMode set --enable true
Maintenance mode is already enabled.
# esxcli system maintenanceMode set --enable false
# esxcli system maintenanceMode get
Disabled

I made these scripts for this:

  • esxcli-maintenanceMode-show.sh:
    #!/bin/sh
    esxcli system maintenanceMode get
  • esxcli-maintenanceMode-enter.sh:
    #!/bin/sh
    esxcli system maintenanceMode set --enable true
  • esxcli-maintenanceMode-exit.sh:
    #!/bin/sh
    esxcli system maintenanceMode set --enable false

Note I have not checked the exit codes for these esxcli commands yet, but did blog about how to do that: Busybox sh (actually ash derivative dash): checking exit codes.

–jeroen

Posted in BusyBox, Development, Encoding, ESXi6, ESXi6.5, ESXi6.7, ESXi7, Power User, Software Development, Unicode, Virtualization, VMware, VMware ESXi | Leave a Comment »

<3 "Minimum Defendable Product": it is part of "Minimum Viable Product".

Posted by jpluimers on 2021/04/21

An important concept in [Archive.is] Kristian Köhntopp on Twitter: “<3 “Minimum Defendable Product”. Das ist ein wichtiges Konzept, das übernehme ich in meinen Sprachgebrauch.… “ quoting

[Archive.is] Mario Hachemer on Twitter: “Ich hab einen Vortrag gehalten zu dem Thema IT Security in Start-ups. Einen Begriff den ich zu dem Zweck definiert hab war das “Minimum Defendable Product” im Kontrast zum MVP. Es bietet sich an als Startup kritisch zu ermitteln welche Assetklassen man sichern kann. Das spart.… “

It is from this thread (also a threat) [Archive.is] Kristian Köhntopp on Twitter: “Operational excellence… “:

Operational excellence

Secrets gehören nicht in Source. Keine SSL Keys, keine Datenbank Passworte, und auch sonst nichts.

In Source gehört Code, der Secrets aus einem Secrets Service (Vault et al) holt, oder, wenn man einige Jahre hinterher ist, aus Files, die von hierasecrets gebaut werden.
Auch zum Testen gehören keine Secrets in den Code. auch hier können Testkeys wie in Production provisioniert werden und nach dem Test verworfen werden (wenn man will)

Die Option, Secrets im Code zu haben muss im Code Review angemeckert werden.
Willkommen in 2021, willkommen zu Operational Excellence.

[Wayback] docs.aws.amazon.com/config/latest/…
Hier die passende AWS OE Security Pillar

The first tweet quoted a surprise about the Luca App (which is highly controversial in Germany: it is a Corona contact tracing app which has some [Wayback] severe security issues):

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Posted in Conference Topics, Conferences, Development, Event, Security, Software Development | Leave a Comment »

XSLT for DUnit TXMLTestListener output

Posted by jpluimers on 2021/04/21

I totally missed this, even though the file has been around for a very long time:

Related: Some links on DUnit, JUnit and NUnit XSD specifications of their XML formats (JUnit is actually Ant XML)

–jeroen

Posted in Delphi, Development, DUnit, Software Development | Leave a Comment »

Busybox sh (actually ash derivative dash): checking exit codes

Posted by jpluimers on 2021/04/20

Even if you include a double quotes "sh" in a Google search to force only sh (in the early days this was the Thompson shell, but nowadays usually a Bourne shell or derivative) results, almost all unix like scripting examples you find are based on bash (the Bourne again shell), so I was glad I dug a bit deeper into what the actual Busybox shell is.

I wanted to know which shell Busybox uses and what capabilities it has, as ESXi ships with this very slimmed down set of tools (called applets in Busybox speak).

It does not even include ssh: that gap is often filled by [Wayback] Dropbear SSH, which was used by ESXi and named dbclient (I think with ESXi 6.0 it was replaced with a more regular ssh implementation): [Wayback] How to compile a statically linked rsync binary for ESXi.

Busybox shell source code is at [Wayback] ash.c\shell – busybox – BusyBox: The Swiss Army Knife of Embedded Linux and indicates the shell is the ash (the Almquist shell) derivative dash (yes, you guessed it right: the Debian Almquist shell), ported from NetBSD and debianized:

 * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
 * was re-ported from NetBSD and debianized.
...
//config:   The most complete and most pedantically correct shell included with
//config:   busybox. This shell is actually a derivative of the Debian 'dash'
//config:   shell (by Herbert Xu), which was created by porting the 'ash' shell
//config:   (written by Kenneth Almquist) from NetBSD.

nx like systems have a shell hell similar to Windows DLL hell: there are too many, and their differences and be both subtle and frustrating. To get a feel, browse through Source: Comparison of command shells – Wikipedia (yes, some shells from other operating environments like DOS, OS/2, VMS and Windows, but the majority is nx).

Since ash is sufficiently different from bash (for example [Wayback] ash – exit code for a piped process), I always want to know what shell code (which often comes from bash as it is so ubiquitous) will work.

There is hardly any shell documentation at the Busybox site. There is [Wayback] BusyBox – The Swiss Army Knife of Embedded Linux, the source code at [Wayback] ash.c\shell – busybox – BusyBox: The Swiss Army Knife of Embedded Linux does not offer much either,

A manual page of it is at [Archive.is] ash(1) [minix man page]. There you see the age: back then, “exit status” is used where nowadays many people would use “exit code”. It does not explain how to check for specific exit codes.

Because ash is derived from the Bourne shell, this page was of great help for me to grasp exit code handing: [Wayback] Exit Codes – Shell Scripting Tutorial

A Bourne Shell Programming / Scripting Tutorial for learning about using the Unix shell.

Here two examples from that page to get me going:

#!/bin/sh
# Second attempt at checking return codes
grep "^${1}:" /etc/passwd > /dev/null 2>&1
if [ "$?" -ne "0" ]; then
  echo "Sorry, cannot find user ${1} in /etc/passwd"
  exit 1
fi
USERNAME=`grep "^${1}:" /etc/passwd|cut -d":" -f1`
NAME=`grep "^${1}:" /etc/passwd|cut -d":" -f5`
HOMEDIR=`grep "^${1}:" /etc/passwd|cut -d":" -f6`

echo "USERNAME: $USERNAME"
echo "NAME: $NAME"
echo "HOMEDIR: $HOMEDIR"

and

#!/bin/sh
# A Tidier approach

check_errs()
{
  # Function. Parameter 1 is the return code
  # Para. 2 is text to display on failure.
  if [ "${1}" -ne "0" ]; then
    echo "ERROR # ${1} : ${2}"
    # as a bonus, make our script exit with the right error code.
    exit ${1}
  fi
}

### main script starts here ###

grep "^${1}:" /etc/passwd > /dev/null 2>&1
check_errs $? "User ${1} not found in /etc/passwd"
USERNAME=`grep "^${1}:" /etc/passwd|cut -d":" -f1`
check_errs $? "Cut returned an error"
echo "USERNAME: $USERNAME"
check_errs $? "echo returned an error - very strange!"

This basically means that status code handling is the same as in bash, so constructs can be used like [Wayback] bash – How to check the exit status using an if statement – Stack Overflow:

$? is a parameter like any other. You can save its value to use before ultimately calling exit.

exit_status=$?
if [ $exit_status -eq 1 ]; then
    echo "blah blah blah"
fi
exit $exit_status

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Posted in *nix, *nix-tools, ash/dash, ash/dash development, bash, bash, BusyBox, Development, Power User, Scripting, Software Development, ssh/sshd | 1 Comment »

Windows DLL and EXE rebase

Posted by jpluimers on 2021/04/20

Some links on rebase for Windows DLLs and EXE files, including effects on .NET CLR.

–jeroen

Posted in .NET, Delphi, Development, Software Development, Windows Development | Leave a Comment »

Since when is the PLATFORMTARGETS resource included in non-package binaries?

Posted by jpluimers on 2021/04/20

A while ago, I discovered that most (if not all) Delphi compiled Windows binaries contain the PLATFORMTARGETS resource.

This is a resource introduced in Delphi XE2 meant to be included in package binaries only.

The documentation back then clearly indicates this:

Relatively recent documentation too: [WayBack] 64-bit Windows Application Development – RAD Studio: Making Your Components Available at Design Time and Run Time

Still all my Delphi compiled binaries contain the PLATFORMTARGETS resource.

When did the compiler behaviour change to include PLATFORMTARGETS in ALL binaries?

–jeroen

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Posted in Delphi, Development, Software Development | Leave a Comment »

Spring4D conference materials

Posted by jpluimers on 2021/04/15

From a while ago, but still very relevant:

Materials

Timeline

twitter.com/search?q=%23Spring4D&src=typd

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Posted in Delphi, Development, Software Development | Leave a Comment »

MSSQL – searching in DDL metadata comments

Posted by jpluimers on 2021/04/14

Some interesting queries at [WayBack] www.nlaak.com • Просмотр темы – Полезные скрипты (English translation by Google)

I have put them in the [WayBack] gist below, and expect that they should be solvable without depending on deprecated sys.sysobjects.

Related: [WayBack] sql server – Making sense of sys.objects, sys.system_objects, and sys.sysobjects? – Database Administrators Stack Exchange

–jeroen

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Posted in Database Development, Development, Software Development, SQL, SQL Server | Leave a Comment »

Plastic SCM: show the current changeset abstract (without files) on the commandline

Posted by jpluimers on 2021/04/14

I could not find a syntax for “current changeset”, but since cm log accepts the output of cm status as changeset identifier:

for /F "tokens=*" %l in ('call cm status --nochanges') do (call cm log %l --itemformat )

Or in batch file form:

for /F "tokens=*" %%l in ('call cm status --nochanges') do (call cm log %%l --itemformat )

Two important parts of the trick that ensure each command only outputs what is needed:

  1. The empty --itemformat specification for cm log indicates that no details about files should be logged.Without it, cm log will list both the changeset information and information about each item in the changeset.
  2. The other trick is --nochanges for cm status: it only shows the status line, and no other changes.Without it, cm status will emit one line per changed file.

–jeroen

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Posted in Development, Encoding, PlasticSCM, Software Development, Source Code Management | Leave a Comment »